Sam stated publicly what his teammates and coaches at Mizzou have known since August: "I am an openly, proud gay man."
Sam is eligible for the NFL draft in May. Assuming that he is drafted, Sam could become the first openly gay player in the history of the NFL.
"I understand how big this is," he said. "It's a big deal. No one has done this before. And it's kind of a nervous process, but I know what I want to be ... I want to be a football player in the NFL."
In 2014, "Gay Man to Enter Workforce" has the everyday-occurrence sound of a headline in The Onion. But when the NFL is involved, it's a first -- and potentially a landmark moment -- in the history of American sports.
Sam's decision to speak out now -- in interviews with ESPN and the New York Times -- comes after his experience two weeks ago at the Senior Bowl, where, he said, many already seemed aware of his sexual orientation.
"I didn't realize how many people actually knew, and I was afraid that someone would tell or leak something out about me," he said. "I want to own my truth. ... No one else should tell my story but me."
He had already confided in a few close friends, Sam recalled, and had dated a fellow athlete who was not a football player -- so while coming out to his Mizzou teammates last year was a key moment, it came almost as an afterthought, during preseason training camp.
"Coaches just wanted to know a little about ourselves, our majors, where we're from, and something that no one knows about you," Sam said. "And I used that opportunity just to tell them that I was gay. And their reaction was like, 'Michael Sam finally told us.' "
Asked what that moment felt like, Sam said, "I was kind of scared, even though they already knew. Just to see their reaction was awesome. They supported me from Day One. I couldn't have better teammates. ... I'm telling you what: I wouldn't have the strength to do this today if I didn't know how much support they'd given me this past semester."
He did not ask them to keep his revelation a secret.
Missouri coach Gary Pinkel said in a statement that he's proud of Sam.
"We're really happy for Michael that he's made the decision to announce this, and we're proud of him and how he represents Mizzou," Pinkel said. "Michael is a great example of just how important it is to be respectful of others, he's taught a lot of people here first-hand that it doesn't matter what your background is, or your personal orientation, we're all on the same team and we all support each other."
Raised in the small town of Hitchcock, Texas, Sam said he grew up uncertain about what his sexual orientation was.
"I knew from a young age that I was attracted to guys," he said, "I didn't know if it was a phase ... I didn't want to say, 'Hey, I might be gay. I might be bi.' I just didn't know ... I wanted to find who I was and make sure I knew what was comfortable. So I didn't tell anyone growing up."
It was an upbringing, he said, filled with adversity.